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Otari MX5050BQII Sound on Sound Mod

Otari MX5050BQII Sound on Sound Mod

November 14th, 2010  |  Published in Otari MX5050BQII, Photos  |  1 Comment

I modified my Otari MX5050BQII 1/4″ 4 track tape machine for sound on sound (SOS). The work is pretty simple. All you need to do is install a switch that enables/disables each track’s erase head. When the erase head is enabled, the machine records normally, erasing the prior signal before writing the new signal to tape. When the erase heads are disabled, the signal is not erased before recording new signals, which results in the live signal being continuously stacked on top of the previously recorded signals. It’s a pretty cool effect that can be used to create nice over-saturation, delay-like effects, lo-fi punch ins, etc.

The unmodified headstack.

Close up of the unmodified headstack.

The modified headstack. I used SPDT (mom)-off-on switches for each head and installed them on top of the headstack case.

Close up of the modified erase heads.

Close up of the modified heads.

The SOS switches installed.

The SOS switches installed.

The SOS switches installed, viewed from below.


  1. microluv says:

    April 13th, 2012at 12:25 pm(#)

    hello there,
    I have been using the otari for recording electronic music. But it’s time for maintenance! any chance you have the manual pdf?

    More importantly:
    I really wanna hear the results of this modification you made, sounds incredible.


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